Why does my car handle funny?

[TRE Cup]

I wish i had a picture of a 356 we saw. The mid west owner was really concerned about the rust on his cabriolet- the car was literally bending in half. Rather than get the replacement floor pans and other metal parts to repair to original, he opted to put simple flat sheet and then had a very elaborate separate boxed frame made up. Incredible amount of work with the resulting car losing 3 inches of ground clearance. Remarkably the car was very solid and stable- but obviously did nothing to keep the value there